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(from tobacco) and conine (from bemlock). Like these, it 
unites with acids and forms salts of aniline, which are soluble 
in water, whilst aniline itself is very slightly soluble in this 
liquid. For the rest, it is colourless, has a strong and peculiar 
odour, mixes easily with alcohol and ether, and decomposes 
slowly in contact with the air. 
We have seen that one of the characteristics of aniline is 
to produce with bleaching powder, or, in fact, with any 
other oxydising agent — a magnificent purple blue colour, 
which, however, soon disappears again. It was in endea- 
vouring to produce this purple blue in a permanent form that 
Mr. W. Perkin first obtained, in 1856, the well-known mauve 
dye. The discovery of the aniline dyes was thus made in 
England. Mr. Perkin took the sulphate of aniline, more or 
less pure, and (to oxydise it) mixed it with a solution of bi- 
chromate of potash acidulated with sulphuric acid. In ten or 
twelve hours a blackish looking powder was deposited ; this 
was collected upon a filter, washed with water, and afterwards 
digested with coal-naphtha, to purify it. It was then dissolved 
in wood- spirit (methylic alcohol), and when this solution was 
evaporated it yielded the new dye in a pure state. So great is 
its colouring power, and so rich the tint produced, that T V of a 
grain of mauve dye will colour substantially a whole gallon of 
alcohol ! Until lately it was, weight for weight, as valuable as 
gold. Mr. Perkin has recently communicated to the Pro- 
ceedings of the Royal Society an elaborate paper upon the 
composition of this mauve dye. It appears to consist es- 
sentially of mauveine, C 54 H 24 N 4 , a powerful organic base, 
uniting with acids like rosaniline, whose composition we shall 
see presently. Dr. Hofmann has also published, in the same 
journal, a numerous series of papers upon the nature and 
composition of the aniline dyes in general. 
Dr. Hofmann appears to have been the first to produce 
aniline red (magenta, rosaniline, fuchsine) as a scientific 
curiosity. He obtained it by acting upon aniline with strong 
nitric acid, and although this process has since been adopted 
in some manufactories. Professor Hofmann did not make any 
use of his discovery. The first patent taken out for the pro- 
duction of rosaniline was that of Messrs. Yerguin & Penard, 
of Lyons, who obtained the colour by the action of bichloride 
of tin upon aniline. Since then many patents have been 
granted for obtaining different shades of aniline dyes by 
different processes, and great success in the production of 
these marvellous colouring matters has attended, in this 
country, the energetic efforts of Messrs. Simpson, Maule, & 
Nicholson. We must here pause for an instant to refer to 
some curious results lately obtained by Dr. Hofmann, which 
